Ultra high frequency receiving device



June 2,1942.v LU I 2,284,829

ULTRA H IGH FREQUENCY RECEIVING DEVICE Filed Mrch 6, 1941 enerator.order to achieve asuper-regenerative effectnevertheless a device isarranged after the inductor electrodes which effects a variation in theelectron velocity and divides the the oscillations demodulated accordingto the super-regenerative method can be tapped of! at the secondarywinding of the transformer l6. With, the arrangement shown in Fi 2 thevelocities are sorted out after the inductorl by means of a magneticileldM directed perpendicular to the electron beam, and .which is forinstance produced by a permanent magnet. The

magnetic fleld deflects the high speed electrons other hand, if thegenerator oscillates, most of the electrons due to their loss of kineticenergy will .be strongly retarded in the inductor so that the otherelectrode will now naturally receive a large part of the current and theamount of current at the first electrode will be correspondinglyreduced. A resistance arrangement can thus be connected into the circuitof one of these electrodes from which demodulated oscillationswithcomparatively high power can be taken. The periodic fulfillment andnon-fulfillment of the conditions of self-excitation for the generatorwith feed-back in accordance with the auxiliary frequency could thenoccur in the usual merger by varying the effective acceleration vol e.

only very slightly so that they reach the anode If. The slow speedelectrons are,' however, strongly-deflected and pass to the secondelectrode 19, to whose circuit the transformer I8 is a connected, thedemodulated oscillations being Since, however, the acceleration voltagewith phase-focused electron beams affects the phase condition of thefeed-back, this would have avery detrimental eifect on the selectivity.Furthermore a periodic variation of the acceleration voltage in rhythmwith the auxiliary frequency causes a continuous variation in the beamvelocities so that the aforementioned device for the velocityvariationdoes not give the desired optimum result. Under these circumstances itis better whilst maintaining the effective accelfeed-back condition theamplitude of the auxiliary oscillation should be given such a magni--erationi voltage constant to alter periodically tude that at least;onceduring its period the intensity of the electron beam is reduced to zeroduring a time interval which is a multiple of. a period-of theself-excite yltra hmh frequency .oscillatiomAsslioWi'i'n Figs. 1 and 2of the drawing this is best done by means of a special grid I I locatedbetween the cathode! and the acceleration electrode 5 which receives thenecessary control voltages over the secondary winding of a high frequenctransformer "from, an oscillator II which produces'the auxiliaryoscillation,- .and which periodically regulates the electron stream inthe desired manner. .The' control element i1 is preferably supplied fromthe battery M with a-negative bias voltage relative to the cathode 2 ofthe phase-focused ultra high frequency generator I. In Fig. 1 theauxiliary oscillator ISis shown in detail whilst in Fig. .2 it is onlyindicated diagrammatically.

The device for sorting out the velocities as shown in Fig. 1 consists ofimposing a bias voltage on the anode I: through the transformer 16, thisvoltage being negativewith respect to the acceleration voltage. Theanode B'thus acts as a retarding. electrode. When the generator does notoscillate the anode l3 receivesrthe entire electrode beam, whilst whenthe generator oscillates a large part of the electrons passing throughthe inductor 'I reverse-their direction in the energy given off bytakenirom the secondary winding of this transformer. In this arrangementwhen the generator isnot oscillating, practically no current flowsthrough the electrode l9, whilst with anoscillating generator thecurrent passing through the electrode It increases rapidly on account ofthe electrons in the inductor.

With both the arrangements described it is a great advantage that theeffective acceleration voltage is independent of both the auxiliaryoscillation of the oscillator l5 and. the demodulated oscillations, sothat it is possible-to apply the super-regenerative methodfor thedemodulation of modulated ultra high frequency waves and obtain a veryhigh eillciency. Iclaim: I 1-. A device for the reception ofiultra highfrequency waves comprising a phase focusing osciliation tube including acathode, an acceleratingelectrode, a modulator, an inductor separatedtherefrom. by a-transit space, said'modulator and inductor beingconnected to a com! mon oscillation system in such manner that the Iratio of the modulator voltage to the inductor". voltageis less thanunity-and self-excited oscillation is caused, and ade'modulatingelectrode system positioned beyond the inductor, means formaintaining a constant effective accelerating voltage between thecathode and ,the accelerat-l ing electrode and an auxiliary oscillatingcircuit 2. A device as defined in claim 1 in which the demodulatingelectrode system comprises at least two electrodes and circuit elementsincluding an impedance for tapping oi! the oscillations imposed on thereceived high frequency waves from at least one of said electrodes.

3. A device for the reception of ultra high frequency waves comprising aphase focusing hos,-

cillation tube. including a cathode,;an accelerat .ingelectrode,-I'a-modulator, an inductorv -ieparatedtherefrom by.a,.transitspace, said modulator "and inductor being connected toa. commonoscillation system in such manner thattheratio o1v the ,modulatorvoltage. to the inductor voltage is less thanunity and selfrexcitedoscillation is caused, and 'a;.demodulating electrode system positionedbeyond the inductor, means for maintaining a constant effectiveaccelerating:

a voltage between the cathode and the accelerat-.

ing electrode and an auxiliary oscillating cir cuit connected to anelectrode positioned between the cathode and the accelerating electrodeof said oscillation tube to vary the beam current; intensityperiodically-at the frequency at whichthe oscillationsproduced insaid'oscilcreases when the generator is osclllatingso that lationsystemare interrupted,'

4. A device as defined in claim 1 inwhich the demodulating electrodesystem comprises at least two electrodes, means providing a magneticiield in said tube beyond the inductor to divide the electron beambetween the electrodes of the demodulating electrode system, and-circuitelements including an impedance for tann s of: the oscillations imposedon the received high frequency waves from at least one oi saidelectrodes.

5. A device as defined in claim 1 including means for impressing on thedemodulating electrode a potential relative to the cathode of theoscillation tube which is smaller than the acceleration voltage.

6. A device for the reception oi ultra high frequency waves comprising aphase focusing oscillation tube including a cathode, an acceleratingelectrode, a modulator, an inductor sepa- 7 rated therefrom by a transitspace, saidmodu circuit connected to said later and inductor beingconnected to a common oscillation system in such manner that the ratioof the modulator voltage to the inductor voltage is less than unity andself-excited oscillation is caused, and a demodulating electrode systempositioned beyond the inductor, means for maintaining a constanteflective accelerating voltage between the cathode and the accelcratingelectrode, and an auxiliary oscillating oscillation tube to vary thebeam current intensity periodically at an amplitude such'that at leastonce during its period the intensity of the electron beam is reducedsubstantially to zero during a time interval which is a multiple of theperiod of the selfexcited high frequency oscillations.

mrrz 113m."

